Stem cell treatment could cure blindness

A revolutionary stem cell treatment developed by British scientists could restore sight in the blind.

In a world first, blindness has been cured by replacing worn out and damaged retinal cells with stem cells.

Experts described the research as "stunning" and said the transplants could transform the lives of hundreds of thousands of Britons who have lost their sight - with the first operations taking place within a decade.

Among those who could benefit are sufferers of macular degeneration - the most common cause of blindness in the elderly - and those who have lost their sight as a complication of diabetes.

Eye surgeon Dr Robert MacLaren said there are 300,000 people with macular degeneration and the number is going to treble in the next 25 years as people get older.

"To have something in our pockets that might be a treatment we could offer patients is very exciting," he said.

The researchers, from University College London and London's Moorfields Eye Hospital, used stem cells - blank cells with the power to turn into different types of cells - to restore the vision in blind mice.

The cells were injected into the back of the eye where they replaced damaged photoreceptors - tiny light-sensitive cells found in the retina and key to vision.

The decay and death of these delicate cells is responsible for blindness in the developed world than all other causes of blindness put together.

Until now was no way of reversing the damage, with all previous stem cell transplants failing.

Central to the success of the technique was the selection of stem cells which were slightly more mature than those tried by other researchers.

These cells both turned into photoreceptors and successfully connected with the nerves leading to the brain.

By shining light into the animals' eyes, the researchers were able to show that vision had been restored to around a quarter of normal levels.

Increasing the number and type of cells transplanted could improve sight even further.

Most of the photoreceptors transplanted were rods - the cells used in peripheral and night vision.

Transfer of cones, sister cells involved in viewing detail and colour, would greatly improve the result.

While stem cells are often obtained from embryos in the first days of life, it is thought the patient's own eye could hold a bank of cells suitable for transplant.

Researcher Professor Robin Ali, of University College London's Institute of Ophthalmology, said: "Recent research has shown that a population of cells found on the margin of the adult retina have stem cell-like properties, in other words, they are capable of self-renewal.

"These could be harvested through minor surgery and grown in the lab before being re-implanted onto the retina."

Using the patient's own cells would also avoid the possibility of 'foreign' cells being rejected by the body.

The scientists caution that the technique is still in its infancy. However, they are hopeful of the first human photoreceptor transplants taking place within ten years.

"Most of the patients I see have eye disease that results in death of the photoreceptors. This research is the first to show photoreceptor transplantation is feasible.

"We are now confident that this is the avenue to pursue to uncover ways of restoring vision to thousands who have lost their sight."

The technique could also be adapted to create stem cells capable of repairing the brain cells destroyed in Parkinson's disease or nerve cells damaged in spinal injuries.

Eye experts described the research, funded by the Medical Research Council, as 'stunning'.

Andrew Dick, Professor of Ophthalmology, University of Bristol, said: "This study shows for the first time that cells transplanted into the retina of mice can integrate and can function as photoreceptors.

"As with any basic research we have to be careful not to overhype, however this is a stunning piece of research that may in the distant future may lead to transplants in humans to relieve blindness."

Pete Torkington, of the Macular Disease Society, said: "This is a very exciting development. It could transform the lives of those with macular degeneration."